Air conditioning units which are commonly used for residential and similar application generally are contained within a single casing. This casing is usually divided by a partition into an evaporator section and a condenser section, each section having its own fan to circulate air therein. The air conditioning unit is normally mounted with the evaporator section communicating with the room air to be conditioned and the condenser section communicating with external air such as outside air. Refrigerant flows through the self contained refrigerant circuit removing heat from the room air and discharging heat to the outside air.
In addition to the capability of the air conditioning unit to provide temperature controlled air to the room, it is desirable for the unit to have means for exhausting unwanted room air from the room to the outside. This is accomplished by the location of a port in the partition separating the condenser section from the evaporator section. A part of the room air enters the evaporator section of the unit and is forced by the evaporator and condenser fans through the port into the condenser section communicating with outside air.
Since the port must be selectively open when the unit is in the exhaust mode of operation, that mode in which part of the unwanted room air is being exhausted, and closed when the unit is in the separate mode of operation to condition the room air, a door is provided to cover the port and a control mechanism is necessary to maintain the door in the appropriate position.
Previous door control mechanisms, while effective, have been relatively complex, requiring numerous parts and considerable skill and effort to assemble the parts. Moreover, prior mechanisms have been awkward to operate and have required the exertion of considerable force to change door positions. Furthermore, mechanisms of the preceding type have tended to make access to the interior of the unit for service more difficult.